Coding apparatus



L. E. WOOD CODING APPARATUS Oct. 26, 1948.

4 SheetsSheet 1 Filed Dec. 29, 1944 INVENTOR AOUI fi/V .5 W000 A ORNEY Get. 26, 1948. WOOD 1 2,452,090

CODING APPARATUS Filed Dec. 29, 194 1 4 Sheets-Sheet 2 INVENTOR ZOUI A/V f. 14 000 BY Oct; 26, 1948. E. WOOD 2,452,090

CODING APPARATUS Filed Dec. 29, 1944 4 Sheets-Sheet 3 INVENTOR 400/4 5. W000 BY eo zazzmw ATTORNEY L. E. WOOD CODING APPARATUS Filed Dec; 29, 1944 4 Sheets-Sheet 4 INVENTOR Mal AW l l/OOfl Patented Oct. 26, 1948 UNITED STATES CODING APPARATUS Louvan E. Wood, Baltimore, Md, assignor to Bendix Aviation Corporation, South Bend, Ind, a corporation of Delaware Application December 29, 1944, Serial No. 570,402

OFFICE 12 Claims. (Cl. 177-351) The present invention relates to measuring apparatus and more particularly to apparatus of the character embodying means for converting the measurements into indications which may be transmitted to a distance.

Although apparatus of this general character have been previously proposed, they have not been altogether satisfactory for the reason that frictional and other forces have been set up which have introduced substantial error into the indi- Figure 3 is a schematic view showing the circation. cuit for the electrical components of Figures 1 I have discovered that by associating with the and 2, and also disclosing the time-controlled movable measuring member a motor driven sweep means for controlling the various circuits; and or scanning element, and providing switch means also the scanning device. which will be closed when the parts are moved Figure 4 is a top plan view, similar to Figure 2, into angular coincidence, and gripping the measbut shows amodified coding mechanism also uring member momentarily at the time of switchforming part of the invention. ing, and providing a coding mechanism, embody- With continued reference to the drawings, in ing a circuit controlled by the scanning switch, which like reference characters have been emthe magnitude of the measurement being made ployed to designate similar parts throughout the may be accurately converted into an indication several views, and referring first to Figures 1 which may be readily transmitted to a distance and 2, the coding mechanism is mounted upon by telegraph or radio. a suitable base il having a pair of upstanding It is accordingly the primary object of the side plates I2 and I3 secured thereto. As seen present invention to provide a novel measurement; in Figure 2, a main driving motor M is secured transmitting apparatus in which the act of conto side plate 12 by means of a plurality of screws vetting the measurement into a transmittible ini5 and spacers It. The shaft of motor [4 carries dication does not exert any frictional or torquing a drive pinion H which meshes with an idler gear forces which would exert rotative error deflecting I8, journaled on a post 9 carried by plate l2. Gear the measuring from its true position and which is I8 meshes with a gear I9 which is journaled on of simple, eflicient, rugged, and yet low cost deshaft 2! which is anchored at its ends in the sign. side plates.

Another important object is to provide a meas- A coding disc 22 has a hub 23 journaled upon urement or condition transmitting apparatus emshaft 2i. Disc 22 is provided with 10 groups of bodying cod-ing wheels which are automatically '35 Morse code defining projections upon which the rotated for a period proportional to the measuremeasurement to be transmitted is set up. As ment being made, the wheels embodying Morse or seen in Figure 1, each group comprises long proother code representations on their peripheries jections 2i and short projections 25. The comand being combined in novel manner with a bination of projections of any one group is difsweeping contact assembly designed to transform 40 ferent from that of any other group. In the presthe measurement into a series of electrical iment instance they run from zero in a clockwise pulses. direction to 9, as indicated. The coding wheel Another object is to provide a measuring apis driven in a clockwise direction (Figure 1) by paratus embodying novel measurement scanning motor It, in the manner which will now be deand measurement coding mechanisms controlled scribed. to operate in proper sequence by a timing mech- Gear W has a hub 21 which rigidly carries a anism, to take an indication from a condition cam 28. The latter cooperates with a pin 20 or measuring instrument having a member movcarried by the end of a bell-crank lever 29, which able in accordance with the measurement or conis rigidly carried by a hub member 3! journaled dition, and convert it into a form of indication on a shaft 32, and which is anchored in the side which is transmittible to a distance. plates. Also secured to hub 3| is a lever 33, which The invention also aims to provide a measuris pivotally connected at its lower end to a pawl ing apparatus embodying novel actuating, reset- 34. The latter cooperates with the teeth of a ting, scanning, and indication transmitting mechratchet wheel 35 which is rigidly secured to hub anisms. 23, for unitary rotation with the coding wheel.

Pawl 34 is urged into engagement with its ratchet by means of a spring 36, and is provided with an inclined end face 3'l which rides against a pin 38 carried by bracket 39 on the base, for the purpose of preventing the code wheel from being advanced by more than one ratchet tooth for each actuation ofithepawl, inthe manner, to .be hereinafterpointed out.

Reverse rotation of the ratchet wheel and coding disc assembly is prevented by means of. a pawl 4| pivoted at 42 on, a bracket assembly l and having its end urged into engagement with the ratchet wheel teeth by ,meansof a coiled spring 42. Bracket 39 is. also provided with a slotted portion 43 for guiding pawl 34.

From the structure so far described, it is apparent that motor 14, through gears H,'-l8'-and 19 will rotate cam 28, and that for each rotation of the cam, levers 29 and 33 will undergo a complete reciprocation causing pawl 34 tofirst be moved to theright and engaged in: they next tooth of ratchet wheel 35, andto-then be reciprocated to the 'left'toadvance the coding'wheel one step. Since inclined face 3l"ofithe"pawl is "engaged-with pirr38"at the"end of the stroke of the pawhthe device is self-lockingand there is no possibility of rotational momentum carrying the coding'wheel through -two'or' more steps; As will be hereinafter pointed out,-the'codingwheel is rotated rearwardly with'respect to'the code representations; Therefore, the longer the peri- 0d of rotation of motor M-the lower the reading will be.

When the coding wheelhas been' brought into coding position, i. '.,'"mOtOI" [ti hes-completed its -period of rotation,-the selected group of Morse code projections is'swept over by a switch as- Y sembly for converting the reading into an indiation which may be transmitted-to a distance.

1 This mechanism will now-be described.

Secured to side plate l2 is a coding 'motor lfi,

carrying a'gear 41 which meshes with a-gear48 rigidly secured to a-shaft 49 journaled-im the sideframes. Rigidly -secured -to' shaft -49 is a 11 hubmember to which is secured a disc? 52 and a pair'ofsliprings-53 and-54. The latter-cooperate with a pair of brushes 55- carried bya brush prises a plate 5'! secured to the disc -by screws 58 -and having a pivotme'mber fia upon 'which a switch member 6| is pivoted. Each-switch-member has a contact portion 62 which is urgedintd engagementwith a'contact screw 'iit'lziy means of a tension spring. 1 Screw-63 is insulatingly 'mounted on a support-'65 carriedby plate"5l,--and is connected to one of the slip rings by a lead -66. the plates 57, so that when the'parts are in the r position shown in Figure l, a circuit is-completed between the slip rings-by screw 63 and mom ber 62.

As seen in Figure 2, the parts are so dimen sioned that afinger B'lprovided on each switch is adapted to rotate in theplaneof rotation of it the coding wheel, and to sweep overthe'Morse The other slip ring is connected to each of code representations thereof, it beingobserved that each time finger Bl rides 'over a projection it will open the circuit between the slip rings for a-period of time depending "upon the circumferential lengthiof,the'projection. For instance, in the position of-the partsdllustrated inFigure 1"; if disc 52 wererotated-clockwise;-as indicated;

.lQ and the resulting signal will, therefore, be given three times, the switches being connected to the 'slip rings in series so that opening any one of .themwillopen the slip ring circuit.

'. -The resulting signal, in the form of current in- .terruptions, may be transmitted to a distance in any well known manner, as for instance over a wire. or :telegra'phically, or it may be introduced into .the transmitter of a radio and broadcast in well known manner.

In order to lock motor 46 across the line upon initiationof the coding-operation; a-disc-GS is rigidly secured to'shaft' 49 and is provided-"with a-notch-ll-inwhich the roller l2- of a switch 'l3 1 is adapted toseatin the position of the parts shown in Figures -1-and 2. ":Rolle'nlz is -carried --byan arm-14,: pivoted on the switch body, in cooperating relationship with-the switch-actuating pin- 15. The parts are-so designed' that when roller 12 is seated in the notchinithe disc, the switch is open, and when it:rides out of the notch the switch is closed. The manner in'which the'switch is associated with thencircuit will be 1 hereinafter set forth.

' After motor M has rotated the coding-:wheel intothe transmitting position and is stopped; and motor-146 .has caused the switches to sweep over the selected group oftMorse-c'ode projections'gtthe device is automatically :fires'etf or restored: to zero or starting position bythe mechanismwhich will now be-described.

Secured tosideplateil-z is a=..resetting motor rllhaving a shaft 78 arigidlycarrying .aazpinion 'lfi. The latter meshes with aagearttllxiournaledrxon a pin 82 carried b-y side plate'sgltzrandi rigidly carrying a pinion'83 which;.rn.eshes .with atgear -.:85 rigidly securedto a1shafttfiaiournaled:irrthe side. frames; ShaftJSE causes a-;resetting -;train 'of'gearing tosbe meshed 'withgearseonthe: code :wheel; and theresetting gear- :train: iscenergized ".by .gear- 84 in the manner that willrnowsbecset -::forth.

Shaft 86 carries a notched disc 81 whichaco- --operates-1with the rol1er-,-88; of a 'sW-i:tcht89,. the v a. roller ,being mounted ona-an'arm 9 I, andcoacting "with a-rswitchv-act-uating pin;92.'I fThiSj forms a holding ;,-circuit;- for the-resetting ymotorq in:- -the mmannerr that will; be described later.

- ;J ournaled on a shaft 93, which1 in turn iswjournaled inthe upper portionsofithe sidewirames, 2 is arswingingframe assembly :madempof a hub 1 port-ion: 94:; and atpair. of: tsiderarmsiflfi; and-I96, which are rigidly interconnected by a DQ511914, A shaft-9B is journaled in theiends of:the;side:arms 95 a and 96 andwrigidly carries a;-.spur 2 gears 99, 5/:which is adapted to be meshedzwith aspur: gear i D l secured by screw :andspacer assemblies tozthe coding wheel.'! The -parts .aremadapteduztozube brought in 13021118511 when thenframe isaswung downwardly, .suchdownward movement ".being 7 limited by a "set'screw lll2, which coacts witli'the upper edge of 'side'lplato 13:1"The .frame is lifted-or swung away from operative position-by means of I an armll33-having ahub =rig'idlyi'cairried by i the fr-ameandhaving a =pin'-l 04 at its lo-wer end" 'disposed in the path of rotation of a cam lBS-seured to shaft 86. The frame is urged downwardly by means of a tension spring I95 secured to lever I93, and anchored to a pin IIi'I carried by side plate I3.

Accordingly, when cam I55 is disposed in the position illustrated in Figure 1, the swinging frame will be held in the elevated position illustrated against the action of spring I05, and when shaft 85 is rotated so as to allow pin I94 to ride off of the raised portion of the cam, gear 99 will be brought in to mesh with code wheel gear IIJI. It'should be observed that in the position of the parts illustrated, drive pinion 59 is disposed opposite blank or mutilated portion I99 of gear IBI where there are no teeth, with the result that if the resetting operation should be initiated with the parts so disposed, no rotation of the code wheel would occur.

The resetting spur pinion 99 is driven in the following manner. Gear 84 rigidly secured on motor shaft l8 meshes with an idler III carried by support IIZ onthe side plate, and itin turn meshes with a gear H5 which is rigidly secured to shaft 53. Secured to the latter, outwardly of side plate I3, is a gear I I4 meshing with an idler I I5 carried by a post on frame member 96, and in turn meshing with a gear H5 rigidly secured to shaft 98. From the foregoing it is apparent that rotation of motor II in a counter-clockwise direction (Figure 1), will, through the two gear trains, rotate shafts 86 and 98 in similar directions. counterclockwise rotation of gear 99, when the latter is meshed with the teeth ofgear I9 I, rotates the coding wheel clockwise. In order to prevent pawl 34- from interfering with clockwise rotation of the coding wheel during resetting it is retracted as follows. A plate I I5 is pivoted at H9 and carand I38. The cams. are angularly spaced to initiate the various operations at the appropriate times, in the manner that will now be set forth.

The measuring instrument or condition indicating device may be of any desired character, so long as it embodies a member which is movable in response to the measurement or the indication. In the present instance the invention has been illustratedas applied to a pressure instrument embodying a bellows I4I which may be expanded or contracted in response to fluid pressures, and it is provided with a reciprocable rack I42 meshing with a pinion I43 carried by shaft I44. In expanding and contracting, the bellows accordingly produces rocking movement of shaft I44, and the latter carries a pointer I for indicating the pressure. scale I46 (diagrammatically illustrated), and also cooperating therewith is a clamping member I 41 ries pins I 2I and I 22 cooperating respectively with pawl 34 and lever 33, so that in response to counter-clockwise rocking of plate II8 lever 33 will be pulled back and pawl-34 will be depressed so as to clear the teeth of ratchet 35. Plate H8 is rigidly secured to a shaft I23 which extends outwardly of side frame I3 and carries a lever I24 (shown in solid lines in Figure 1 for sake of clarity). The latter is connected by link I25 to a bell crank lever I26, pivoted on a post I2! and having a pin I28 on its lower end coacting with a disc I29 having a recess I3I. In the position of parts shown in Figures 1 and 2, pin I28 is disposed in recess ISI. Spring I32 normally maintains the parts in this position, and it is connected to lever I25 and is anchored in a-suitable part of the frame.

From the foregoing it is apparent that when shaft 86 is rotated counter-clockwise from the position illustrated in Figure 1, cam I29 will rock lever I25 counter-clockwise, and through link I25 will rock plate H8 in a similar direction, causing pin I22 to move lever 33 to the right and causing pin I2I to depresspawl 34 against the action of spring 36. The projection on cam I05 will ride out from under pin I04, thereby allowing spring I95 to depress the frame and bring spur gear 99 into mesh with gear IIII, which is now free to turn and which will be rotated clockwise until blank portion. I99 of gear I9! is brought opposite spur pinion 59, whereupon the coding wheel will have attained its starting position.

Referring now to Figure 8, which shows the novel scanning mechcanism of the invention and also the circuit for controlling the electrical components of the device shown in Figures 1 and 2, a shaft I 95 is driven at constant speed in any suitable manner, as for instance by a clock or a constant speed motor, and carries cams I36, I31

carried by an arm I48 pivoted at I49 and actuated by a solenoid I5I. The solenoid clamps the pointer momentarily during the period the pressure is being scanned, and prevents the switch contacts from affecting the position of the pointer. As will be readily understood, clamping member I41 (only a portion of which has been shown), extends over the entire range of movement of pointer I45, so as to grip the latter in any rocked position.

Scanning is carried out by means of an arm I52 carried by a shaft I53 and having a switch element I54 cooperating with a switch element I55 on pointer I45. Shaft I 53 is rotated by a motor I55 at reduced speed through a speed reducing mechanism (not shown). Shaft I53 also carries a notched disc I57 which cooperates with the roller I58 of a switch I59. Power is supplied by lines I6I and I52, and the device is placed in operation by cam I32 lifting roller I63 of a switch I64, as seen in Figure 3. The switch has one side connected to line I62 and the other side is connected by means of leads I 65 and I66 to motor I56 and solenoid I5! respectively. One side of motor I58 is permanently connected to the line by a lead I51.

It is accordingly apparent that with the parts in the positions illustrated, and with switch I54 closed, motor I55 will start and the latter will rotate disc I57, thereby'lifting roller I58 out of its notch and closing switch I59. Closure of switch I55, through a lead I63, places motor I55 across the line independently of lead I65, and also, through a lead I59, completes the circuit of solenoid I5 I, causing it to energize ring I47 and clamp the pointer. With the parts in the positions just described, pointer I45 is clamped and arm I52 is being rotated'in the direction indicated by shaft I53. It should be observed that arm I52 has been illustrated as being angularly displaced (clockwise) from its true position with respect to disc I51, in order to show the coaction betwen contacts I54 and I55. Upon rotation of shaft I53 through a predetermined distance, depending upon the position into which pointer I45 has been actuated by bellows I4I (scale indication 3 in Figure 3) switch part I54 of the arm will engage switch part I55 of the pointer, thereb closing a circuit through a lead III to line I5 I, and through a lead I12 to one side of a solenoid I13. The other side of the solenoid is connected by a lead I14 to a contact H5, and by a lead I to lead I55.

A second contact I II is connected to lead I'I'l, the parts being so arranged that upon energization of the solenoid in response to arm I52 attaining an angular position coinciding with the The pointer cooperates with a.

easement pointer; itsrcontactiarm"IT8willbe energized by thersolenoidand. engage contact I TI and maintain the solenoid energized subsequent to disengagement'iofacontactzparts:I 54 and: i 55; by means of a leadxl 19 which connects-contact arm I I8 :directly to; line GI: secondnontactiarmcml actuated by; thersolenoid engagesrcontact I15: and starts neri just: described, the pointer will be clamped,

and contacts 'I 54 and-I 55'will momentarilyenga and energize c relay or solenoid I13, which :in turn I holds: itself :acrosspthe line by: means of contact armcl'l8; andaa second contact arm 'I BI starts the codingawheel motor. Itisalso apparent that the codings'motonrwill .continue'to run until disc I51 hasrotatedsufiiciently forlroller: I 58 to again drop intwthenotch; When-this occurs, switch I 59 opens;causing-vsolenoid 415i to be de-energized, thereby? releasing clamp-141; and alsode-energizing relay I13," which-in turn opens contact arms l'l8'and IB I-and stopping motor I4. By mean'srof' the foregoing. structure motor I4 is energizediora perioddepending: upon the time contact I54 of the rotating arm first engages contact l55"-of'the pointer, and it continues to run for-the balance of rotation of arm I52.

Assuming that'scale l lI-i of the instrument is graduated from 1 to 10, and that the pointer is standing at numeral 3 as indicated, the contact will beclosed when arm I52 moves into an angular position coinciding therewith, and motor I4 will start at'that instant and will run for the entire balance'of rotation'of the arm, namely, approximately of a revolution; While the foregoing operation is taking place, motor I4 rotates coding wheel 22 clockwise, it being remembered'that the code representationsare so arranged that stepby-step'operationcausesithe values to progressively decrease. Therefore, the foregoing operation will bring the 7th group of Morse code projections representing numeral 3 into cooperation with switches 61.

M is at its minimum indication (1, in the illustrated embodiment), the code unit will commence counting at the'beginning of the scanning period,- with the result that the final number will below. Conversely, if pointer I45is at its maximum" indication, the COdGzdIlit will not start to be' advanced st'ep-by-step '(or counted down), untilthe very end of the-scanningoperation, with the result that-the final number will be high.

Upon completion of the operation justdescribed; all the parts are de-energlzed except shaft I35, which has in the meantime moved the projection; of cam I38 beyond roller I 63. The projection on cam lalnow engages the roller I81 of a switch "I88,v which is connected at one side to line 162; by lead I89, and at the other side, by

means of leads HM and I 92, to switch '13 and; motor respectively. Switch 13 is connected to line I62 by arlead I93, and motor 46'isconnectedL to line IiSI :by means of :a lead "194;" a condenser I95; and'a second lead I 95 When switch I88 is closed inthe manner just Motor 46', which operates the scanning mocha- In other words, if pointer Lil 8?? nisnr;willathereforezrun-for:a rsufi'icient length-sofa I time to, rotate shaft 2 4.9 a full :revolution, and: causeeachof' the-switch" fingers 6'! to ride over"- therprojections-of; the code wheelwhich are -10,- cated in thegcoding station. The .slipiirings 53.and; 54- of theacod-in fswitches:are connected ?byleads-z i953 and-l99fto line-J61 and to thetelegraphic; radio or other l signal -transmitting device. Upon conclusion of the operation just'described, roller 12'; seats-iitseli-l in :the notch of disc 69; thereby' opening switch :73 and stopping ,motor- 46, inasv muchras the :plOjeCtionr-of cam I31 -hasxnowrrotatedabeyondz' roller: 181: This completes thecoding-roperatiom The projection-:01 cam.-l36 now 'lifts'roller 2M: otaswitch-202; which is connected at onesside rto line I62 by means of a lead 203,- andcatithezothertside by, meansof leads 204' and 205, to resetemotor =11- andw switch 89 respectively. Switch 89 iis also connected: to lead I 93; The other side zof motor 'I'I is connected to; line-'- IB-I r by-mea-ns of leads 206l-and 20'! and a condenser 203. -Upon' rotation of disc' 8'1, in response to operation of motor: I1,- roller- 88 islifted out of its notch" and..- closes: switch 89, thereby connect; i ing motor 11 across the :line by way of leads I 93 r and- 208,. independently of switch 202; The resetting=operation'is-then carried out bymoton H andiitsgeartrains, inthe mannerpreviously set-forth, and-upon conclusion thereofroller 88 againeseats in its notch fi'L-opening switch 89 and,.-stcpping-;motor 'I'I, inasmuch as the projection of; cam I36} has in" the meantime I opened switch-192;. The-devicehas now completed'a full cycle ofoperation; and upon further rotation of shaft I35-the sequence of operations which have justt-been described;will be automatically repeated;

Thev embodiment of theinvention just de-- scribeddeals with the transmission; of measure'- mentswwhichwinvolve-a single digit;- -If'it is desired totransmit information involving :two or more i'digits; this mayjzbe readily carried out by adding thenecessary number of code wheels and coding. switches to..the mechanism.

In the modificationof the invention illustrated in Figure: 4 there? is, disclosed: an zembodiment of: the apparatusg'designed 'forthe transmission of information involving three digits, and inas-v much as :many of ithesparts are 1' similar :to: those. of the zfornnof: the invention just described, the same 'referencezlcharacters; with the subscript a, will be employed to designate corresponding; parts:

' Motor I 4a1is: energized in the? same manner" as before andricarriesagear 2! I 'meshing with a pinion 2I2 'journaled' 0n shaft 21a and rigidly connected' to cam- 2804: Cam -28a actuates lever 29a: and pawl 34c in' the manner previously described; thereby: advancing ratchetrwheel 35a andlits icod-ing wheel 22a": in the manner pre-J vicusly set .forthJTIn this-instance, thev hub of coding wheeli 22a also carries a :cam 1 28b; similar to ca-mi 28'agzwhich in turn actuatesa lever 29b. The ilatt'er, througha-pawl 34b, rotates a ratchet wheel 35bI 1=andxa rigidly connected second codex wheel -22b:

From the foregoing it' is apparent that for each rotation: of cam 28'a, in response to rotation of pinion 2I2', coding'wheel 22a 'will be advanced-"one -step; and that for every-completerevolutiozr ofcoding wheel 22a, coding wheel 22b will-be advanced one stepionetenth of a revolu-' tiOHQ-j In similar-manner; a cam-28c carried bycoding wheel-ewl will rock lever l9c and actuate 9 pawl 340 in suchmanner as to advance ratchet wheel 35c, which is rigidly connected to a third coding wheel 220. From the foregoing it is apparentth'at any desired number up to 999 may be set up on the code wheels.

In this'instance the coding, switch, assembly is made up of three'discs 52a, 52b, and 520,,each of which carries three switches, and the latter arez'disposed in staggeredrelationship so that a switch of disc 52a will first sweep over the projections of coding wheel 22a, followed by similar sweeping operation by a switch of disc 52b, and then by 'a switch of disc 520, so as to make proper sequence in the-transmitting circuit, it being understood that each disc may carry three switches a 'before, spaced 120 apart-with respectto each other. Three successive transmissions of each digit set up on the coding wheels will accordingly be made. I

The resetting mechanism is also similar to that previously set forth, except that in this instance motor Fla is disposed inwardly of frame member |3a to conserve space, and the reducing gear train is located outwardly thereof. Also, it is to be observed that frame members 95 and 95 are spread sufiiciently to permit three reset spur gears 99a, 99b and 990 to be secured on shaft 98a. The resetting operation is the same as that previously set forth, except that in this case the three resetting spur pinions are simultaneously'brought into mesh with reset gears lllla, lillb, and Mile of the respective code wheels, and since none of the wheels need be rotated a full revolution to return it to starting position, the resetting operation is just as rapid as with thesingle wheel form. The pawls are retracted by a plurality of plates similar to plate l is and actuated by bell-crank lever l26a,in the manner described in conjunction with the first form of the invention.

From the foregoing detailed disclosure of the invention it is apparentthat novel apparatus are provided which will take an indication from a measuring or condition indicating device and, without setting up any force in such device which would introduce error into the readings, will transform or convert the reading into the form of electrical impulses or other form of signal which may be readily transmitted to a distance by telegraph, radio, or by other transmission media well known in the art.

The invention may be embodied in other specific forms without departing from the spirit or essentialcharacteristics thereof. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced thereby.

What is claimed and desired to be secured by United States Letters Patent is:

1. In a signaling apparatus, a rotatable code wheel; power means, including ratchet means, for advancing said code wheel step-by-step; ratchet means for preventing retrograde rotation of said code wheel, the latter having a plurality of sets of code-defining projections around its periphery; a structure mounted for rotation adjacent said code wheel and carrying switch means having a finger adapted to ride over the set of projections of said code wheel located nearest said device; and time-controlled means for advancin said code wheel for a predetermined period; means for rotating said device after advance of said code wheel has ceased; and resetting means for returning said code wheel to a predetermined starting, position subsequent to completion of rotation of said device.-

2. The apparatus defined in claim 1, wherein said first-named ratchet means is also operable to prevent advance of said code wheel between steps, and said resetting means is operable to rendersaid first-named ratchet means inoperative while said code wheel is being returned to starting position. 1

3. Theapparatus-defined in claim 1, wherein said projections lie along an are, having a radius of curvature substantially equal to the path of.

rotation defined by the end of the switchffinger.

4. In a measuring apparatus, in combination with a measuring instrument having a member movable in accordance with the magnitude of the measurement; means for gripping said member and holding it stationary independently of "the magnitude of the measurement and havingoperative and inoperative positions; an element mounted for movement coextensive with the path of travel of said member; switch means adaptedv to be automatically closed when said member and position when said element has completed its full range of movement.

6. The measuring apparatus defined in claim 14, wherein said coding means comprises a rotatable wheel having a plurality of groups of codedefining projections on its periphery and a motor drivingly connected to said wheel and automatically controlled by said circuit for advancing said wheel through an angular distanceproportional to the time of closure of said switch means, and

means coacting with the selected group'of pro jections of said wheel, for converting the position of said wheel into an indication which may be transmitted to a distance.

7. In a data transmission system, a condition responsive element, a coding member provided with a plurality of zone groups of differing characteristics, a setting motor controlled by said condition responsive element, a set drive linkage conmeeting said setting motor and said coding member, a reset motor, a reset drive linkage connecting said reset motor and said coding member adapted to interrupt the driving connection when said coding member occupies a predetermined reference position, and means for disabling said set drive linkage during the reset operation.

8. In a data transmission system, a condition responsive element, a set member, a setting motor controlled by said condition responsive element, at set drive linkage connecting said setting motor and said set member, a reset motor, a reset drive linkage connecting said reset motor and said set member adapted to interrupt the reset driving connection when said coding member occupie's a predetermined reference "position; ian'dz J- means actuated byflsaid reset motor- :for disabling 9. -In a data transmissionsystem; a code-menu: ber-f-provid'edwith a plurality or 120119 grou l of l differing characteristics, a set motor, an inter'b mittent drive connection linking" said set irnotor ana -said? code -member whereby diiferentizone disabling s'aidintermittent"drive connection and bringing saidreset driViiitg; surface into engage ment with saidreset driven 'surface; and means for reading out the zone group characteristics 'at said readin g I stationi i r Ina data transmissionsystem, a code mem ber pr0viddwitha pluralityiof zone groups of difieringcharacteristics,a set motor, a set" drive linkage iconnectin'g said'set motor and said code member :whereby idifl'erent zone groups. may be positionedat a reading station, means for readr ing-out' ithe zone"groupi'ch'aracteristics at said readingstation, a toothed reset driven "surface linked'iwith said code member provided with an interruption *in said teeth ..:--.at" a predetermined reference-=position; a toothed' resetdrivmg surface normallydisengaged from' zsaid 'reset driven surface movabie' into engagement with said reset driven surface; means powering said reset drivingsurface}means for disabling said set drive linkage and bringing-said}: reset-*- driving teeth into!- engagement with said' reset 1 driven teeth, andna stoplimiting the'emovement 0f said reset driving teeth towardrsaid reset driven teeth;

11.? InIa" data transmission systemgacode' mem into I engagement with: said reset driven. gear; a reset-motor .-poweringsaid :reset driving gear,

means actuated-bysaid reset motor for disabling- 12 said set drivirig linkage and bringingr said irfesete'ri driving: gear into engagement withfLsaidfl-reset driven gear,"- and a stop limiting the movements: of said resetdrivinglgearitowardrsaid resetdrivem I:

5 igear.

129111 a data transmissionsystem,"a rotatabiy mounted: code wheeli having: :a' periphery provided 6 with a' plurality of zon'e' groups of difiering charf actei istics, a. set mctor; a, set 'driv-ing'linkage con- L10 nectii'igis'aidset motor and said code wheel'where I by' difierenti zone lgroups may: be positioned. at a Ir reading station; meansiorzreading out the zone group: characteristics at -said T reading station, ra J- driveirrotatabiy mounted fries'et gear linkedizwith a riplieral' teeth thereof, a reset arm pivote'd r-ior rotation about: an axis parallel' to the axis of rotation Qf-Js'aid:driven' reset gear; a reset driving gear journaled 1onrthe fre'end of'sai'dreset 5mm" movable into -'engagement withsaid reset driven'ge'ar upon' rotationof said reset arm, :a stoptlimitingthe' travel of said reset driving gear toward s'aid reset drivengearya resetmotor'pow ering s'aidlreset' driving gear, and means actuated bysaid Freset i'notor for-displacing said "reset arrri and disabl-ing s'ai'd set driving linkage;

LOUVAN WOOD.

REFERENCES CITED lfhfollowingreferences"are ofrecord in the file of this patent:

UNITED STATES-PATENTS Number- Name'- 1 Date 1 313,147 Wilson Mar.'-3, 1885' 1,620Q405 'Sptenger Mar.- 8, 192'? 1,621,939 1 Lower Mar,'22,"1925 137855940 Enn'es' e Dec. 23,1930 1,965,393 Schleicher et al.- -July 3, 1934 2,085,415; Chauveau- 1.. June:29, .-193'7 2,099,982'i Ko'enig- Nov: 23, 193? u' 2,146g189 Kin'er Feb; '7, 1939: 2,1'48jO75- Kinerf; .d Feb. 21,- 1939 2207;733: Larson et ali. Ju1y'16,"1940i- 2,239;094v Harvey Apr. 22,1941 2,279,282 1 Graham" 1 Apr; '7, 19423 2,290,753 Kecklev; "July 21, 1942 23091117 John Jan. 26, 1 1943... 2,329,370 Hicks/1 c: i. Septil, "19431 FOREIGN PATENTS Number Country Date 23,234 Austraiia July 27, 1936 

